drm_irq.c 52.6 KB
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Daniel Vetter 已提交
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/*
 * drm_irq.c IRQ and vblank support
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 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
 *
 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

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#include <drm/drmP.h>
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#include "drm_trace.h"
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#include "drm_internal.h"
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#include <linux/interrupt.h>	/* For task queue support */
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#include <linux/slab.h>
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#include <linux/vgaarb.h>
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#include <linux/export.h>
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/* Access macro for slots in vblank timestamp ringbuffer. */
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#define vblanktimestamp(dev, crtc, count) \
	((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
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/* Retry timestamp calculation up to 3 times to satisfy
 * drm_timestamp_precision before giving up.
 */
#define DRM_TIMESTAMP_MAXRETRIES 3

/* Threshold in nanoseconds for detection of redundant
 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
 */
#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000

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static bool
drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
			  struct timeval *tvblank, unsigned flags);

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static unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */

/*
 * Default to use monotonic timestamps for wait-for-vblank and page-flip
 * complete events.
 */
unsigned int drm_timestamp_monotonic = 1;

static int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */

module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);

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static void store_vblank(struct drm_device *dev, int crtc,
			 unsigned vblank_count_inc,
			 struct timeval *t_vblank)
{
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
	u32 tslot;

	assert_spin_locked(&dev->vblank_time_lock);

	if (t_vblank) {
		/* All writers hold the spinlock, but readers are serialized by
		 * the latching of vblank->count below.
		 */
		tslot = vblank->count + vblank_count_inc;
		vblanktimestamp(dev, crtc, tslot) = *t_vblank;
	}

	/*
	 * vblank timestamp updates are protected on the write side with
	 * vblank_time_lock, but on the read side done locklessly using a
	 * sequence-lock on the vblank counter. Ensure correct ordering using
	 * memory barrriers. We need the barrier both before and also after the
	 * counter update to synchronize with the next timestamp write.
	 * The read-side barriers for this are in drm_vblank_count_and_time.
	 */
	smp_wmb();
	vblank->count += vblank_count_inc;
	smp_wmb();
}

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/**
 * drm_update_vblank_count - update the master vblank counter
 * @dev: DRM device
 * @crtc: counter to update
 *
 * Call back into the driver to update the appropriate vblank counter
 * (specified by @crtc).  Deal with wraparound, if it occurred, and
 * update the last read value so we can deal with wraparound on the next
 * call if necessary.
 *
 * Only necessary when going from off->on, to account for frames we
 * didn't get an interrupt for.
 *
 * Note: caller must hold dev->vbl_lock since this reads & writes
 * device vblank fields.
 */
static void drm_update_vblank_count(struct drm_device *dev, int crtc)
{
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	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
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	u32 cur_vblank, diff;
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	bool rc;
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	struct timeval t_vblank;

	/*
	 * Interrupts were disabled prior to this call, so deal with counter
	 * wrap if needed.
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	 * NOTE!  It's possible we lost a full dev->max_vblank_count + 1 events
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	 * here if the register is small or we had vblank interrupts off for
	 * a long time.
	 *
	 * We repeat the hardware vblank counter & timestamp query until
	 * we get consistent results. This to prevent races between gpu
	 * updating its hardware counter while we are retrieving the
	 * corresponding vblank timestamp.
	 */
	do {
		cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
		rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
	} while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));

	/* Deal with counter wrap */
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	diff = cur_vblank - vblank->last;
	if (cur_vblank < vblank->last) {
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		diff += dev->max_vblank_count + 1;
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		DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
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			  crtc, vblank->last, cur_vblank, diff);
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	}

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	DRM_DEBUG("updating vblank count on crtc %d, missed %d\n",
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		  crtc, diff);

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	if (diff == 0)
		return;

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	/*
	 * Only reinitialize corresponding vblank timestamp if high-precision query
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	 * available and didn't fail. Otherwise reinitialize delayed at next vblank
	 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
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	 */
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	if (!rc)
		t_vblank = (struct timeval) {0, 0};

	store_vblank(dev, crtc, diff, &t_vblank);
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}

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/*
 * Disable vblank irq's on crtc, make sure that last vblank count
 * of hardware and corresponding consistent software vblank counter
 * are preserved, even if there are any spurious vblank irq's after
 * disable.
 */
static void vblank_disable_and_save(struct drm_device *dev, int crtc)
{
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	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
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	unsigned long irqflags;
	u32 vblcount;
	s64 diff_ns;
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	bool vblrc;
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	struct timeval tvblank;
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	int count = DRM_TIMESTAMP_MAXRETRIES;
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	/* Prevent vblank irq processing while disabling vblank irqs,
	 * so no updates of timestamps or count can happen after we've
	 * disabled. Needed to prevent races in case of delayed irq's.
	 */
	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);

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	/*
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	 * If the vblank interrupt was already disabled update the count
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	 * and timestamp to maintain the appearance that the counter
	 * has been ticking all along until this time. This makes the
	 * count account for the entire time between drm_vblank_on() and
	 * drm_vblank_off().
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	 *
	 * But only do this if precise vblank timestamps are available.
	 * Otherwise we might read a totally bogus timestamp since drivers
	 * lacking precise timestamp support rely upon sampling the system clock
	 * at vblank interrupt time. Which obviously won't work out well if the
	 * vblank interrupt is disabled.
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	 */
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	if (!vblank->enabled &&
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	    drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0)) {
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		drm_update_vblank_count(dev, crtc);
		spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
		return;
	}

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	/*
	 * Only disable vblank interrupts if they're enabled. This avoids
	 * calling the ->disable_vblank() operation in atomic context with the
	 * hardware potentially runtime suspended.
	 */
	if (vblank->enabled) {
		dev->driver->disable_vblank(dev, crtc);
		vblank->enabled = false;
	}
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	/* No further vblank irq's will be processed after
	 * this point. Get current hardware vblank count and
	 * vblank timestamp, repeat until they are consistent.
	 *
	 * FIXME: There is still a race condition here and in
	 * drm_update_vblank_count() which can cause off-by-one
	 * reinitialization of software vblank counter. If gpu
	 * vblank counter doesn't increment exactly at the leading
	 * edge of a vblank interval, then we can lose 1 count if
	 * we happen to execute between start of vblank and the
	 * delayed gpu counter increment.
	 */
	do {
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		vblank->last = dev->driver->get_vblank_counter(dev, crtc);
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		vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
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	} while (vblank->last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
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	if (!count)
		vblrc = 0;
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	/* Compute time difference to stored timestamp of last vblank
	 * as updated by last invocation of drm_handle_vblank() in vblank irq.
	 */
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	vblcount = vblank->count;
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	diff_ns = timeval_to_ns(&tvblank) -
		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));

	/* If there is at least 1 msec difference between the last stored
	 * timestamp and tvblank, then we are currently executing our
	 * disable inside a new vblank interval, the tvblank timestamp
	 * corresponds to this new vblank interval and the irq handler
	 * for this vblank didn't run yet and won't run due to our disable.
	 * Therefore we need to do the job of drm_handle_vblank() and
	 * increment the vblank counter by one to account for this vblank.
	 *
	 * Skip this step if there isn't any high precision timestamp
	 * available. In that case we can't account for this and just
	 * hope for the best.
	 */
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	if (vblrc && (abs64(diff_ns) > 1000000))
		store_vblank(dev, crtc, 1, &tvblank);
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	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
}

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static void vblank_disable_fn(unsigned long arg)
{
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	struct drm_vblank_crtc *vblank = (void *)arg;
	struct drm_device *dev = vblank->dev;
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	unsigned long irqflags;
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	int crtc = vblank->crtc;
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	if (!dev->vblank_disable_allowed)
		return;

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	spin_lock_irqsave(&dev->vbl_lock, irqflags);
	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
		DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
		vblank_disable_and_save(dev, crtc);
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	}
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	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
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}

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/**
 * drm_vblank_cleanup - cleanup vblank support
 * @dev: DRM device
 *
 * This function cleans up any resources allocated in drm_vblank_init.
 */
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void drm_vblank_cleanup(struct drm_device *dev)
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{
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	int crtc;

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	/* Bail if the driver didn't call drm_vblank_init() */
	if (dev->num_crtcs == 0)
		return;

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	for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
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		struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

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		WARN_ON(vblank->enabled &&
			drm_core_check_feature(dev, DRIVER_MODESET));
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		del_timer_sync(&vblank->disable_timer);
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	}
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	kfree(dev->vblank);
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	dev->num_crtcs = 0;
}
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EXPORT_SYMBOL(drm_vblank_cleanup);
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/**
 * drm_vblank_init - initialize vblank support
 * @dev: drm_device
 * @num_crtcs: number of crtcs supported by @dev
 *
 * This function initializes vblank support for @num_crtcs display pipelines.
 *
 * Returns:
 * Zero on success or a negative error code on failure.
 */
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int drm_vblank_init(struct drm_device *dev, int num_crtcs)
{
	int i, ret = -ENOMEM;

	spin_lock_init(&dev->vbl_lock);
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	spin_lock_init(&dev->vblank_time_lock);

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	dev->num_crtcs = num_crtcs;

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	dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
	if (!dev->vblank)
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		goto err;

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	for (i = 0; i < num_crtcs; i++) {
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		struct drm_vblank_crtc *vblank = &dev->vblank[i];

		vblank->dev = dev;
		vblank->crtc = i;
		init_waitqueue_head(&vblank->queue);
		setup_timer(&vblank->disable_timer, vblank_disable_fn,
			    (unsigned long)vblank);
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	}
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	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
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	/* Driver specific high-precision vblank timestamping supported? */
	if (dev->driver->get_vblank_timestamp)
		DRM_INFO("Driver supports precise vblank timestamp query.\n");
	else
		DRM_INFO("No driver support for vblank timestamp query.\n");

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	/* Must have precise timestamping for reliable vblank instant disable */
	if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
		dev->vblank_disable_immediate = false;
		DRM_INFO("Setting vblank_disable_immediate to false because "
			 "get_vblank_timestamp == NULL\n");
	}

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	dev->vblank_disable_allowed = false;

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	return 0;

err:
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	dev->num_crtcs = 0;
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	return ret;
}
EXPORT_SYMBOL(drm_vblank_init);

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static void drm_irq_vgaarb_nokms(void *cookie, bool state)
{
	struct drm_device *dev = cookie;

	if (dev->driver->vgaarb_irq) {
		dev->driver->vgaarb_irq(dev, state);
		return;
	}

	if (!dev->irq_enabled)
		return;

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	if (state) {
		if (dev->driver->irq_uninstall)
			dev->driver->irq_uninstall(dev);
	} else {
		if (dev->driver->irq_preinstall)
			dev->driver->irq_preinstall(dev);
		if (dev->driver->irq_postinstall)
			dev->driver->irq_postinstall(dev);
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	}
}

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/**
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 * drm_irq_install - install IRQ handler
 * @dev: DRM device
 * @irq: IRQ number to install the handler for
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 *
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 * Initializes the IRQ related data. Installs the handler, calling the driver
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 * irq_preinstall() and irq_postinstall() functions before and after the
 * installation.
 *
 * This is the simplified helper interface provided for drivers with no special
 * needs. Drivers which need to install interrupt handlers for multiple
 * interrupts must instead set drm_device->irq_enabled to signal the DRM core
 * that vblank interrupts are available.
 *
 * Returns:
 * Zero on success or a negative error code on failure.
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 */
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int drm_irq_install(struct drm_device *dev, int irq)
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{
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	int ret;
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	unsigned long sh_flags = 0;
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	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

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	if (irq == 0)
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		return -EINVAL;

	/* Driver must have been initialized */
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	if (!dev->dev_private)
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		return -EINVAL;

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	if (dev->irq_enabled)
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		return -EBUSY;
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	dev->irq_enabled = true;
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	DRM_DEBUG("irq=%d\n", irq);
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	/* Before installing handler */
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	if (dev->driver->irq_preinstall)
		dev->driver->irq_preinstall(dev);
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	/* Install handler */
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	if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
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		sh_flags = IRQF_SHARED;
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	ret = request_irq(irq, dev->driver->irq_handler,
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			  sh_flags, dev->driver->name, dev);
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	if (ret < 0) {
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		dev->irq_enabled = false;
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		return ret;
	}

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	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);

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	/* After installing handler */
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	if (dev->driver->irq_postinstall)
		ret = dev->driver->irq_postinstall(dev);

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	if (ret < 0) {
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		dev->irq_enabled = false;
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		if (!drm_core_check_feature(dev, DRIVER_MODESET))
			vga_client_register(dev->pdev, NULL, NULL, NULL);
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		free_irq(irq, dev);
	} else {
		dev->irq = irq;
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	}
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	return ret;
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}
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EXPORT_SYMBOL(drm_irq_install);
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/**
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 * drm_irq_uninstall - uninstall the IRQ handler
 * @dev: DRM device
 *
 * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
 * This should only be called by drivers which used drm_irq_install() to set up
 * their interrupt handler. Other drivers must only reset
 * drm_device->irq_enabled to false.
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 *
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 * Note that for kernel modesetting drivers it is a bug if this function fails.
 * The sanity checks are only to catch buggy user modesetting drivers which call
 * the same function through an ioctl.
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 *
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 * Returns:
 * Zero on success or a negative error code on failure.
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 */
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int drm_irq_uninstall(struct drm_device *dev)
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{
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	unsigned long irqflags;
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	bool irq_enabled;
	int i;
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	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	irq_enabled = dev->irq_enabled;
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	dev->irq_enabled = false;
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	/*
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	 * Wake up any waiters so they don't hang. This is just to paper over
	 * isssues for UMS drivers which aren't in full control of their
	 * vblank/irq handling. KMS drivers must ensure that vblanks are all
	 * disabled when uninstalling the irq handler.
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	 */
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	if (dev->num_crtcs) {
		spin_lock_irqsave(&dev->vbl_lock, irqflags);
		for (i = 0; i < dev->num_crtcs; i++) {
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			struct drm_vblank_crtc *vblank = &dev->vblank[i];

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			if (!vblank->enabled)
				continue;

			WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));

			vblank_disable_and_save(dev, i);
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			wake_up(&vblank->queue);
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		}
		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
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	}

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	if (!irq_enabled)
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		return -EINVAL;

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	DRM_DEBUG("irq=%d\n", dev->irq);
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	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		vga_client_register(dev->pdev, NULL, NULL, NULL);

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	if (dev->driver->irq_uninstall)
		dev->driver->irq_uninstall(dev);
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	free_irq(dev->irq, dev);
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	return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);

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/*
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 * IRQ control ioctl.
 *
 * \param inode device inode.
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 * \param file_priv DRM file private.
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 * \param cmd command.
 * \param arg user argument, pointing to a drm_control structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls irq_install() or irq_uninstall() according to \p arg.
 */
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int drm_control(struct drm_device *dev, void *data,
		struct drm_file *file_priv)
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{
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	struct drm_control *ctl = data;
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	int ret = 0, irq;
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	/* if we haven't irq we fallback for compatibility reasons -
	 * this used to be a separate function in drm_dma.h
	 */
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	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return 0;
	if (drm_core_check_feature(dev, DRIVER_MODESET))
		return 0;
	/* UMS was only ever support on pci devices. */
	if (WARN_ON(!dev->pdev))
		return -EINVAL;
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	switch (ctl->func) {
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	case DRM_INST_HANDLER:
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		irq = dev->pdev->irq;

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		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
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		    ctl->irq != irq)
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			return -EINVAL;
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		mutex_lock(&dev->struct_mutex);
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		ret = drm_irq_install(dev, irq);
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		mutex_unlock(&dev->struct_mutex);

		return ret;
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	case DRM_UNINST_HANDLER:
581 582 583 584 585
		mutex_lock(&dev->struct_mutex);
		ret = drm_irq_uninstall(dev);
		mutex_unlock(&dev->struct_mutex);

		return ret;
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	default:
		return -EINVAL;
	}
}

591
/**
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 * drm_calc_timestamping_constants - calculate vblank timestamp constants
 * @crtc: drm_crtc whose timestamp constants should be updated.
 * @mode: display mode containing the scanout timings
595
 *
596 597 598
 * Calculate and store various constants which are later
 * needed by vblank and swap-completion timestamping, e.g,
 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
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 * derived from CRTC's true scanout timing, so they take
600
 * things like panel scaling or other adjustments into account.
601
 */
602 603
void drm_calc_timestamping_constants(struct drm_crtc *crtc,
				     const struct drm_display_mode *mode)
604
{
605
	int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
606
	int dotclock = mode->crtc_clock;
607 608 609

	/* Valid dotclock? */
	if (dotclock > 0) {
610 611 612 613 614 615
		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;

		/*
		 * Convert scanline length in pixels and video
		 * dot clock to line duration, frame duration
		 * and pixel duration in nanoseconds:
616
		 */
617 618 619
		pixeldur_ns = 1000000 / dotclock;
		linedur_ns  = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
		framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
620 621 622 623 624 625

		/*
		 * Fields of interlaced scanout modes are only half a frame duration.
		 */
		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
			framedur_ns /= 2;
626 627 628 629 630 631 632 633 634
	} else
		DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
			  crtc->base.id);

	crtc->pixeldur_ns = pixeldur_ns;
	crtc->linedur_ns  = linedur_ns;
	crtc->framedur_ns = framedur_ns;

	DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
635 636
		  crtc->base.id, mode->crtc_htotal,
		  mode->crtc_vtotal, mode->crtc_vdisplay);
637
	DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
638 639
		  crtc->base.id, dotclock, framedur_ns,
		  linedur_ns, pixeldur_ns);
640 641 642 643
}
EXPORT_SYMBOL(drm_calc_timestamping_constants);

/**
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 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
 * @dev: DRM device
 * @crtc: Which CRTC's vblank timestamp to retrieve
 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
 *             On return contains true maximum error of timestamp
 * @vblank_time: Pointer to struct timeval which should receive the timestamp
 * @flags: Flags to pass to driver:
 *         0 = Default,
 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
 * @refcrtc: CRTC which defines scanout timing
 * @mode: mode which defines the scanout timings
 *
 * Implements calculation of exact vblank timestamps from given drm_display_mode
 * timings and current video scanout position of a CRTC. This can be called from
 * within get_vblank_timestamp() implementation of a kms driver to implement the
 * actual timestamping.
660 661 662 663 664 665 666 667 668 669 670 671 672 673
 *
 * Should return timestamps conforming to the OML_sync_control OpenML
 * extension specification. The timestamp corresponds to the end of
 * the vblank interval, aka start of scanout of topmost-leftmost display
 * pixel in the following video frame.
 *
 * Requires support for optional dev->driver->get_scanout_position()
 * in kms driver, plus a bit of setup code to provide a drm_display_mode
 * that corresponds to the true scanout timing.
 *
 * The current implementation only handles standard video modes. It
 * returns as no operation if a doublescan or interlaced video mode is
 * active. Higher level code is expected to handle this.
 *
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 * Returns:
 * Negative value on error, failure or if not supported in current
676 677
 * video mode:
 *
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 * -EINVAL   - Invalid CRTC.
679 680 681 682 683 684 685 686 687 688 689 690 691 692
 * -EAGAIN   - Temporary unavailable, e.g., called before initial modeset.
 * -ENOTSUPP - Function not supported in current display mode.
 * -EIO      - Failed, e.g., due to failed scanout position query.
 *
 * Returns or'ed positive status flags on success:
 *
 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
 *
 */
int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
					  int *max_error,
					  struct timeval *vblank_time,
					  unsigned flags,
693 694
					  const struct drm_crtc *refcrtc,
					  const struct drm_display_mode *mode)
695
{
696
	struct timeval tv_etime;
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	ktime_t stime, etime;
698
	int vbl_status;
699
	int vpos, hpos, i;
700
	int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721
	bool invbl;

	if (crtc < 0 || crtc >= dev->num_crtcs) {
		DRM_ERROR("Invalid crtc %d\n", crtc);
		return -EINVAL;
	}

	/* Scanout position query not supported? Should not happen. */
	if (!dev->driver->get_scanout_position) {
		DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
		return -EIO;
	}

	/* Durations of frames, lines, pixels in nanoseconds. */
	framedur_ns = refcrtc->framedur_ns;
	linedur_ns  = refcrtc->linedur_ns;
	pixeldur_ns = refcrtc->pixeldur_ns;

	/* If mode timing undefined, just return as no-op:
	 * Happens during initial modesetting of a crtc.
	 */
722
	if (framedur_ns == 0) {
723 724 725 726 727 728 729 730 731 732 733 734
		DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
		return -EAGAIN;
	}

	/* Get current scanout position with system timestamp.
	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
	 * if single query takes longer than max_error nanoseconds.
	 *
	 * This guarantees a tight bound on maximum error if
	 * code gets preempted or delayed for some reason.
	 */
	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
735 736 737 738
		/*
		 * Get vertical and horizontal scanout position vpos, hpos,
		 * and bounding timestamps stime, etime, pre/post query.
		 */
739
		vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
740
							       &hpos, &stime, &etime);
741 742 743 744 745 746 747 748

		/* Return as no-op if scanout query unsupported or failed. */
		if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
			DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
				  crtc, vbl_status);
			return -EIO;
		}

749
		/* Compute uncertainty in timestamp of scanout position query. */
750
		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
751 752

		/* Accept result with <  max_error nsecs timing uncertainty. */
753
		if (duration_ns <= *max_error)
754 755 756 757 758 759
			break;
	}

	/* Noisy system timing? */
	if (i == DRM_TIMESTAMP_MAXRETRIES) {
		DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
760
			  crtc, duration_ns/1000, *max_error/1000, i);
761 762 763
	}

	/* Return upper bound of timestamp precision error. */
764
	*max_error = duration_ns;
765 766 767 768 769 770

	/* Check if in vblank area:
	 * vpos is >=0 in video scanout area, but negative
	 * within vblank area, counting down the number of lines until
	 * start of scanout.
	 */
771
	invbl = vbl_status & DRM_SCANOUTPOS_IN_VBLANK;
772 773 774 775 776

	/* Convert scanout position into elapsed time at raw_time query
	 * since start of scanout at first display scanline. delta_ns
	 * can be negative if start of scanout hasn't happened yet.
	 */
777
	delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
778

779
	if (!drm_timestamp_monotonic)
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Thomas Gleixner 已提交
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		etime = ktime_mono_to_real(etime);
781

782 783
	/* save this only for debugging purposes */
	tv_etime = ktime_to_timeval(etime);
784 785 786
	/* Subtract time delta from raw timestamp to get final
	 * vblank_time timestamp for end of vblank.
	 */
787 788 789 790
	if (delta_ns < 0)
		etime = ktime_add_ns(etime, -delta_ns);
	else
		etime = ktime_sub_ns(etime, delta_ns);
791
	*vblank_time = ktime_to_timeval(etime);
792

793 794
	DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
		  crtc, (int)vbl_status, hpos, vpos,
795
		  (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
796
		  (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
797
		  duration_ns/1000, i);
798 799 800

	vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
	if (invbl)
801
		vbl_status |= DRM_VBLANKTIME_IN_VBLANK;
802 803 804 805 806

	return vbl_status;
}
EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);

807 808 809 810
static struct timeval get_drm_timestamp(void)
{
	ktime_t now;

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Thomas Gleixner 已提交
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	now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
812 813 814
	return ktime_to_timeval(now);
}

815 816
/**
 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
817
 *                             vblank interval
818
 * @dev: DRM device
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 * @crtc: which CRTC's vblank timestamp to retrieve
820 821
 * @tvblank: Pointer to target struct timeval which should receive the timestamp
 * @flags: Flags to pass to driver:
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Daniel Vetter 已提交
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 *         0 = Default,
 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
824 825
 *
 * Fetches the system timestamp corresponding to the time of the most recent
D
Daniel Vetter 已提交
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 * vblank interval on specified CRTC. May call into kms-driver to
827 828 829 830 831
 * compute the timestamp with a high-precision GPU specific method.
 *
 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
 * call, i.e., it isn't very precisely locked to the true vblank.
 *
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 * Returns:
833
 * True if timestamp is considered to be very precise, false otherwise.
834
 */
835 836 837
static bool
drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
			  struct timeval *tvblank, unsigned flags)
838
{
839
	int ret;
840 841 842 843 844 845 846 847 848

	/* Define requested maximum error on timestamps (nanoseconds). */
	int max_error = (int) drm_timestamp_precision * 1000;

	/* Query driver if possible and precision timestamping enabled. */
	if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
		ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
							tvblank, flags);
		if (ret > 0)
849
			return true;
850 851 852
	}

	/* GPU high precision timestamp query unsupported or failed.
853
	 * Return current monotonic/gettimeofday timestamp as best estimate.
854
	 */
855
	*tvblank = get_drm_timestamp();
856

857
	return false;
858 859
}

860 861 862 863 864 865 866 867
/**
 * drm_vblank_count - retrieve "cooked" vblank counter value
 * @dev: DRM device
 * @crtc: which counter to retrieve
 *
 * Fetches the "cooked" vblank count value that represents the number of
 * vblank events since the system was booted, including lost events due to
 * modesetting activity.
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 *
869 870
 * This is the legacy version of drm_crtc_vblank_count().
 *
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 * Returns:
 * The software vblank counter.
873 874 875
 */
u32 drm_vblank_count(struct drm_device *dev, int crtc)
{
876 877
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

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	if (WARN_ON(crtc >= dev->num_crtcs))
		return 0;
880
	return vblank->count;
881 882 883
}
EXPORT_SYMBOL(drm_vblank_count);

884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902
/**
 * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
 * @crtc: which counter to retrieve
 *
 * Fetches the "cooked" vblank count value that represents the number of
 * vblank events since the system was booted, including lost events due to
 * modesetting activity.
 *
 * This is the native KMS version of drm_vblank_count().
 *
 * Returns:
 * The software vblank counter.
 */
u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
{
	return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_count);

903 904 905 906 907 908 909 910 911 912 913
/**
 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
 * and the system timestamp corresponding to that vblank counter value.
 *
 * @dev: DRM device
 * @crtc: which counter to retrieve
 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
 *
 * Fetches the "cooked" vblank count value that represents the number of
 * vblank events since the system was booted, including lost events due to
 * modesetting activity. Returns corresponding system timestamp of the time
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Daniel Vetter 已提交
914
 * of the vblank interval that corresponds to the current vblank counter value.
915 916 917 918
 */
u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
			      struct timeval *vblanktime)
{
919
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
920 921
	u32 cur_vblank;

R
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922 923 924
	if (WARN_ON(crtc >= dev->num_crtcs))
		return 0;

925 926 927 928
	/*
	 * Vblank timestamps are read lockless. To ensure consistency the vblank
	 * counter is rechecked and ordering is ensured using memory barriers.
	 * This works like a seqlock. The write-side barriers are in store_vblank.
929 930
	 */
	do {
931 932
		cur_vblank = vblank->count;
		smp_rmb();
933 934
		*vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
		smp_rmb();
935
	} while (cur_vblank != vblank->count);
936 937 938 939 940

	return cur_vblank;
}
EXPORT_SYMBOL(drm_vblank_count_and_time);

941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964
static void send_vblank_event(struct drm_device *dev,
		struct drm_pending_vblank_event *e,
		unsigned long seq, struct timeval *now)
{
	WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
	e->event.sequence = seq;
	e->event.tv_sec = now->tv_sec;
	e->event.tv_usec = now->tv_usec;

	list_add_tail(&e->base.link,
		      &e->base.file_priv->event_list);
	wake_up_interruptible(&e->base.file_priv->event_wait);
	trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
					 e->event.sequence);
}

/**
 * drm_send_vblank_event - helper to send vblank event after pageflip
 * @dev: DRM device
 * @crtc: CRTC in question
 * @e: the event to send
 *
 * Updates sequence # and timestamp on event, and sends it to userspace.
 * Caller must hold event lock.
965 966
 *
 * This is the legacy version of drm_crtc_send_vblank_event().
967 968 969 970 971 972
 */
void drm_send_vblank_event(struct drm_device *dev, int crtc,
		struct drm_pending_vblank_event *e)
{
	struct timeval now;
	unsigned int seq;
973

974 975 976 977
	if (crtc >= 0) {
		seq = drm_vblank_count_and_time(dev, crtc, &now);
	} else {
		seq = 0;
978 979

		now = get_drm_timestamp();
980
	}
981
	e->pipe = crtc;
982 983 984 985
	send_vblank_event(dev, e, seq, &now);
}
EXPORT_SYMBOL(drm_send_vblank_event);

986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002
/**
 * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
 * @crtc: the source CRTC of the vblank event
 * @e: the event to send
 *
 * Updates sequence # and timestamp on event, and sends it to userspace.
 * Caller must hold event lock.
 *
 * This is the native KMS version of drm_send_vblank_event().
 */
void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
				struct drm_pending_vblank_event *e)
{
	drm_send_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
}
EXPORT_SYMBOL(drm_crtc_send_vblank_event);

V
Ville Syrjälä 已提交
1003 1004 1005 1006 1007 1008 1009
/**
 * drm_vblank_enable - enable the vblank interrupt on a CRTC
 * @dev: DRM device
 * @crtc: CRTC in question
 */
static int drm_vblank_enable(struct drm_device *dev, int crtc)
{
1010
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
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1011 1012 1013 1014 1015 1016
	int ret = 0;

	assert_spin_locked(&dev->vbl_lock);

	spin_lock(&dev->vblank_time_lock);

1017
	if (!vblank->enabled) {
D
Daniel Vetter 已提交
1018 1019
		/*
		 * Enable vblank irqs under vblank_time_lock protection.
V
Ville Syrjälä 已提交
1020 1021 1022 1023 1024 1025 1026 1027
		 * All vblank count & timestamp updates are held off
		 * until we are done reinitializing master counter and
		 * timestamps. Filtercode in drm_handle_vblank() will
		 * prevent double-accounting of same vblank interval.
		 */
		ret = dev->driver->enable_vblank(dev, crtc);
		DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
		if (ret)
1028
			atomic_dec(&vblank->refcount);
V
Ville Syrjälä 已提交
1029
		else {
1030
			vblank->enabled = true;
V
Ville Syrjälä 已提交
1031 1032 1033 1034 1035 1036 1037 1038 1039
			drm_update_vblank_count(dev, crtc);
		}
	}

	spin_unlock(&dev->vblank_time_lock);

	return ret;
}

1040 1041 1042 1043 1044 1045 1046 1047
/**
 * drm_vblank_get - get a reference count on vblank events
 * @dev: DRM device
 * @crtc: which CRTC to own
 *
 * Acquire a reference count on vblank events to avoid having them disabled
 * while in use.
 *
1048 1049
 * This is the legacy version of drm_crtc_vblank_get().
 *
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Daniel Vetter 已提交
1050
 * Returns:
1051 1052 1053 1054
 * Zero on success, nonzero on failure.
 */
int drm_vblank_get(struct drm_device *dev, int crtc)
{
1055
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1056
	unsigned long irqflags;
1057 1058
	int ret = 0;

1059 1060 1061
	if (!dev->num_crtcs)
		return -EINVAL;

R
Rob Clark 已提交
1062 1063 1064
	if (WARN_ON(crtc >= dev->num_crtcs))
		return -EINVAL;

1065 1066
	spin_lock_irqsave(&dev->vbl_lock, irqflags);
	/* Going from 0->1 means we have to enable interrupts again */
1067
	if (atomic_add_return(1, &vblank->refcount) == 1) {
V
Ville Syrjälä 已提交
1068
		ret = drm_vblank_enable(dev, crtc);
1069
	} else {
1070 1071
		if (!vblank->enabled) {
			atomic_dec(&vblank->refcount);
1072
			ret = -EINVAL;
1073 1074 1075 1076 1077 1078 1079 1080
		}
	}
	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

	return ret;
}
EXPORT_SYMBOL(drm_vblank_get);

1081 1082 1083 1084 1085 1086 1087
/**
 * drm_crtc_vblank_get - get a reference count on vblank events
 * @crtc: which CRTC to own
 *
 * Acquire a reference count on vblank events to avoid having them disabled
 * while in use.
 *
1088
 * This is the native kms version of drm_vblank_get().
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098
 *
 * Returns:
 * Zero on success, nonzero on failure.
 */
int drm_crtc_vblank_get(struct drm_crtc *crtc)
{
	return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_get);

1099 1100 1101 1102 1103 1104
/**
 * drm_vblank_put - give up ownership of vblank events
 * @dev: DRM device
 * @crtc: which counter to give up
 *
 * Release ownership of a given vblank counter, turning off interrupts
1105
 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1106 1107
 *
 * This is the legacy version of drm_crtc_vblank_put().
1108 1109 1110
 */
void drm_vblank_put(struct drm_device *dev, int crtc)
{
1111 1112
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

R
Rob Clark 已提交
1113 1114
	if (WARN_ON(atomic_read(&vblank->refcount) == 0))
		return;
1115

R
Rob Clark 已提交
1116 1117 1118
	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

1119
	/* Last user schedules interrupt disable */
1120
	if (atomic_dec_and_test(&vblank->refcount)) {
1121 1122 1123
		if (drm_vblank_offdelay == 0)
			return;
		else if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
1124
			vblank_disable_fn((unsigned long)vblank);
1125
		else
1126 1127 1128
			mod_timer(&vblank->disable_timer,
				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
	}
1129 1130 1131
}
EXPORT_SYMBOL(drm_vblank_put);

1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146
/**
 * drm_crtc_vblank_put - give up ownership of vblank events
 * @crtc: which counter to give up
 *
 * Release ownership of a given vblank counter, turning off interrupts
 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
 *
 * This is the native kms version of drm_vblank_put().
 */
void drm_crtc_vblank_put(struct drm_crtc *crtc)
{
	drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_put);

1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161
/**
 * drm_wait_one_vblank - wait for one vblank
 * @dev: DRM device
 * @crtc: crtc index
 *
 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
 * due to lack of driver support or because the crtc is off.
 */
void drm_wait_one_vblank(struct drm_device *dev, int crtc)
{
	int ret;
	u32 last;

	ret = drm_vblank_get(dev, crtc);
1162
	if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", crtc, ret))
1163 1164 1165 1166 1167 1168 1169 1170
		return;

	last = drm_vblank_count(dev, crtc);

	ret = wait_event_timeout(dev->vblank[crtc].queue,
				 last != drm_vblank_count(dev, crtc),
				 msecs_to_jiffies(100));

1171
	WARN(ret == 0, "vblank wait timed out on crtc %i\n", crtc);
1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190

	drm_vblank_put(dev, crtc);
}
EXPORT_SYMBOL(drm_wait_one_vblank);

/**
 * drm_crtc_wait_one_vblank - wait for one vblank
 * @crtc: DRM crtc
 *
 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
 * due to lack of driver support or because the crtc is off.
 */
void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
{
	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_wait_one_vblank);

1191 1192 1193 1194 1195
/**
 * drm_vblank_off - disable vblank events on a CRTC
 * @dev: DRM device
 * @crtc: CRTC in question
 *
D
Daniel Vetter 已提交
1196 1197 1198 1199 1200 1201
 * Drivers can use this function to shut down the vblank interrupt handling when
 * disabling a crtc. This function ensures that the latest vblank frame count is
 * stored so that drm_vblank_on() can restore it again.
 *
 * Drivers must use this function when the hardware vblank counter can get
 * reset, e.g. when suspending.
1202 1203
 *
 * This is the legacy version of drm_crtc_vblank_off().
1204
 */
1205 1206
void drm_vblank_off(struct drm_device *dev, int crtc)
{
1207
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1208 1209
	struct drm_pending_vblank_event *e, *t;
	struct timeval now;
1210
	unsigned long irqflags;
1211
	unsigned int seq;
1212

R
Rob Clark 已提交
1213 1214 1215
	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

1216 1217 1218
	spin_lock_irqsave(&dev->event_lock, irqflags);

	spin_lock(&dev->vbl_lock);
1219
	vblank_disable_and_save(dev, crtc);
1220
	wake_up(&vblank->queue);
1221

1222 1223 1224 1225 1226 1227 1228 1229 1230 1231
	/*
	 * Prevent subsequent drm_vblank_get() from re-enabling
	 * the vblank interrupt by bumping the refcount.
	 */
	if (!vblank->inmodeset) {
		atomic_inc(&vblank->refcount);
		vblank->inmodeset = 1;
	}
	spin_unlock(&dev->vbl_lock);

1232 1233
	/* Send any queued vblank events, lest the natives grow disquiet */
	seq = drm_vblank_count_and_time(dev, crtc, &now);
1234

1235 1236 1237 1238 1239 1240
	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
		if (e->pipe != crtc)
			continue;
		DRM_DEBUG("Sending premature vblank event on disable: \
			  wanted %d, current %d\n",
			  e->event.sequence, seq);
1241
		list_del(&e->base.link);
1242
		drm_vblank_put(dev, e->pipe);
1243
		send_vblank_event(dev, e, seq, &now);
1244
	}
1245
	spin_unlock_irqrestore(&dev->event_lock, irqflags);
1246 1247 1248
}
EXPORT_SYMBOL(drm_vblank_off);

1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267
/**
 * drm_crtc_vblank_off - disable vblank events on a CRTC
 * @crtc: CRTC in question
 *
 * Drivers can use this function to shut down the vblank interrupt handling when
 * disabling a crtc. This function ensures that the latest vblank frame count is
 * stored so that drm_vblank_on can restore it again.
 *
 * Drivers must use this function when the hardware vblank counter can get
 * reset, e.g. when suspending.
 *
 * This is the native kms version of drm_vblank_off().
 */
void drm_crtc_vblank_off(struct drm_crtc *crtc)
{
	drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_off);

1268 1269
/**
 * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
1270
 * @drm_crtc: CRTC in question
1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299
 *
 * Drivers can use this function to reset the vblank state to off at load time.
 * Drivers should use this together with the drm_crtc_vblank_off() and
 * drm_crtc_vblank_on() functions. The difference compared to
 * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
 * and hence doesn't need to call any driver hooks.
 */
void drm_crtc_vblank_reset(struct drm_crtc *drm_crtc)
{
	struct drm_device *dev = drm_crtc->dev;
	unsigned long irqflags;
	int crtc = drm_crtc_index(drm_crtc);
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

	spin_lock_irqsave(&dev->vbl_lock, irqflags);
	/*
	 * Prevent subsequent drm_vblank_get() from enabling the vblank
	 * interrupt by bumping the refcount.
	 */
	if (!vblank->inmodeset) {
		atomic_inc(&vblank->refcount);
		vblank->inmodeset = 1;
	}
	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

	WARN_ON(!list_empty(&dev->vblank_event_list));
}
EXPORT_SYMBOL(drm_crtc_vblank_reset);

V
Ville Syrjälä 已提交
1300 1301 1302 1303
/**
 * drm_vblank_on - enable vblank events on a CRTC
 * @dev: DRM device
 * @crtc: CRTC in question
D
Daniel Vetter 已提交
1304 1305 1306
 *
 * This functions restores the vblank interrupt state captured with
 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1307
 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
D
Daniel Vetter 已提交
1308
 * in driver load code to reflect the current hardware state of the crtc.
1309 1310
 *
 * This is the legacy version of drm_crtc_vblank_on().
V
Ville Syrjälä 已提交
1311 1312 1313
 */
void drm_vblank_on(struct drm_device *dev, int crtc)
{
1314
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
V
Ville Syrjälä 已提交
1315 1316
	unsigned long irqflags;

R
Rob Clark 已提交
1317 1318 1319
	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

V
Ville Syrjälä 已提交
1320
	spin_lock_irqsave(&dev->vbl_lock, irqflags);
1321
	/* Drop our private "prevent drm_vblank_get" refcount */
1322 1323 1324
	if (vblank->inmodeset) {
		atomic_dec(&vblank->refcount);
		vblank->inmodeset = 0;
1325
	}
1326 1327 1328 1329 1330 1331 1332 1333

	/*
	 * sample the current counter to avoid random jumps
	 * when drm_vblank_enable() applies the diff
	 *
	 * -1 to make sure user will never see the same
	 * vblank counter value before and after a modeset
	 */
1334
	vblank->last =
1335 1336
		(dev->driver->get_vblank_counter(dev, crtc) - 1) &
		dev->max_vblank_count;
1337 1338 1339 1340 1341 1342
	/*
	 * re-enable interrupts if there are users left, or the
	 * user wishes vblank interrupts to be enabled all the time.
	 */
	if (atomic_read(&vblank->refcount) != 0 ||
	    (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
V
Ville Syrjälä 已提交
1343 1344 1345 1346 1347
		WARN_ON(drm_vblank_enable(dev, crtc));
	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
EXPORT_SYMBOL(drm_vblank_on);

1348 1349 1350 1351 1352 1353
/**
 * drm_crtc_vblank_on - enable vblank events on a CRTC
 * @crtc: CRTC in question
 *
 * This functions restores the vblank interrupt state captured with
 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1354
 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1355 1356 1357 1358 1359 1360 1361 1362 1363 1364
 * in driver load code to reflect the current hardware state of the crtc.
 *
 * This is the native kms version of drm_vblank_on().
 */
void drm_crtc_vblank_on(struct drm_crtc *crtc)
{
	drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_vblank_on);

D
Dave Airlie 已提交
1365 1366 1367 1368 1369 1370 1371
/**
 * drm_vblank_pre_modeset - account for vblanks across mode sets
 * @dev: DRM device
 * @crtc: CRTC in question
 *
 * Account for vblank events across mode setting events, which will likely
 * reset the hardware frame counter.
D
Daniel Vetter 已提交
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386
 *
 * This is done by grabbing a temporary vblank reference to ensure that the
 * vblank interrupt keeps running across the modeset sequence. With this the
 * software-side vblank frame counting will ensure that there are no jumps or
 * discontinuities.
 *
 * Unfortunately this approach is racy and also doesn't work when the vblank
 * interrupt stops running, e.g. across system suspend resume. It is therefore
 * highly recommended that drivers use the newer drm_vblank_off() and
 * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
 * using "cooked" software vblank frame counters and not relying on any hardware
 * counters.
 *
 * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
 * again.
D
Dave Airlie 已提交
1387 1388 1389
 */
void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
{
1390 1391
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];

1392
	/* vblank is not initialized (IRQ not installed ?), or has been freed */
1393 1394
	if (!dev->num_crtcs)
		return;
R
Rob Clark 已提交
1395 1396 1397 1398

	if (WARN_ON(crtc >= dev->num_crtcs))
		return;

D
Dave Airlie 已提交
1399 1400 1401 1402 1403 1404 1405
	/*
	 * To avoid all the problems that might happen if interrupts
	 * were enabled/disabled around or between these calls, we just
	 * have the kernel take a reference on the CRTC (just once though
	 * to avoid corrupting the count if multiple, mismatch calls occur),
	 * so that interrupts remain enabled in the interim.
	 */
1406 1407
	if (!vblank->inmodeset) {
		vblank->inmodeset = 0x1;
1408
		if (drm_vblank_get(dev, crtc) == 0)
1409
			vblank->inmodeset |= 0x2;
D
Dave Airlie 已提交
1410 1411 1412 1413
	}
}
EXPORT_SYMBOL(drm_vblank_pre_modeset);

D
Daniel Vetter 已提交
1414 1415 1416 1417 1418 1419 1420 1421
/**
 * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
 * @dev: DRM device
 * @crtc: CRTC in question
 *
 * This function again drops the temporary vblank reference acquired in
 * drm_vblank_pre_modeset.
 */
D
Dave Airlie 已提交
1422 1423
void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
{
1424
	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
D
Dave Airlie 已提交
1425 1426
	unsigned long irqflags;

1427 1428 1429 1430
	/* vblank is not initialized (IRQ not installed ?), or has been freed */
	if (!dev->num_crtcs)
		return;

1431
	if (vblank->inmodeset) {
D
Dave Airlie 已提交
1432
		spin_lock_irqsave(&dev->vbl_lock, irqflags);
1433
		dev->vblank_disable_allowed = true;
D
Dave Airlie 已提交
1434
		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1435

1436
		if (vblank->inmodeset & 0x2)
1437 1438
			drm_vblank_put(dev, crtc);

1439
		vblank->inmodeset = 0;
D
Dave Airlie 已提交
1440 1441 1442 1443
	}
}
EXPORT_SYMBOL(drm_vblank_post_modeset);

D
Daniel Vetter 已提交
1444
/*
1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458
 * drm_modeset_ctl - handle vblank event counter changes across mode switch
 * @DRM_IOCTL_ARGS: standard ioctl arguments
 *
 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
 * ioctls around modesetting so that any lost vblank events are accounted for.
 *
 * Generally the counter will reset across mode sets.  If interrupts are
 * enabled around this call, we don't have to do anything since the counter
 * will have already been incremented.
 */
int drm_modeset_ctl(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	struct drm_modeset_ctl *modeset = data;
1459
	unsigned int crtc;
1460 1461 1462

	/* If drm_vblank_init() hasn't been called yet, just no-op */
	if (!dev->num_crtcs)
1463
		return 0;
1464

1465 1466 1467 1468
	/* KMS drivers handle this internally */
	if (drm_core_check_feature(dev, DRIVER_MODESET))
		return 0;

1469
	crtc = modeset->crtc;
1470 1471
	if (crtc >= dev->num_crtcs)
		return -EINVAL;
1472 1473 1474

	switch (modeset->cmd) {
	case _DRM_PRE_MODESET:
D
Dave Airlie 已提交
1475
		drm_vblank_pre_modeset(dev, crtc);
1476 1477
		break;
	case _DRM_POST_MODESET:
D
Dave Airlie 已提交
1478
		drm_vblank_post_modeset(dev, crtc);
1479 1480
		break;
	default:
1481
		return -EINVAL;
1482 1483
	}

1484
	return 0;
1485 1486
}

1487 1488 1489 1490
static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
				  union drm_wait_vblank *vblwait,
				  struct drm_file *file_priv)
{
1491
	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1492 1493 1494 1495
	struct drm_pending_vblank_event *e;
	struct timeval now;
	unsigned long flags;
	unsigned int seq;
1496
	int ret;
1497

1498
	e = kzalloc(sizeof(*e), GFP_KERNEL);
1499 1500 1501 1502
	if (e == NULL) {
		ret = -ENOMEM;
		goto err_put;
	}
1503 1504

	e->pipe = pipe;
1505
	e->base.pid = current->pid;
1506
	e->event.base.type = DRM_EVENT_VBLANK;
1507
	e->event.base.length = sizeof(e->event);
1508 1509 1510 1511 1512 1513 1514
	e->event.user_data = vblwait->request.signal;
	e->base.event = &e->event.base;
	e->base.file_priv = file_priv;
	e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;

	spin_lock_irqsave(&dev->event_lock, flags);

1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526
	/*
	 * drm_vblank_off() might have been called after we called
	 * drm_vblank_get(). drm_vblank_off() holds event_lock
	 * around the vblank disable, so no need for further locking.
	 * The reference from drm_vblank_get() protects against
	 * vblank disable from another source.
	 */
	if (!vblank->enabled) {
		ret = -EINVAL;
		goto err_unlock;
	}

1527
	if (file_priv->event_space < sizeof(e->event)) {
1528 1529
		ret = -EBUSY;
		goto err_unlock;
1530 1531
	}

1532
	file_priv->event_space -= sizeof(e->event);
1533 1534
	seq = drm_vblank_count_and_time(dev, pipe, &now);

1535 1536 1537
	if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
	    (seq - vblwait->request.sequence) <= (1 << 23)) {
		vblwait->request.sequence = seq + 1;
1538
		vblwait->reply.sequence = vblwait->request.sequence;
1539 1540 1541 1542 1543
	}

	DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
		  vblwait->request.sequence, seq, pipe);

1544 1545 1546
	trace_drm_vblank_event_queued(current->pid, pipe,
				      vblwait->request.sequence);

1547 1548
	e->event.sequence = vblwait->request.sequence;
	if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1549
		drm_vblank_put(dev, pipe);
1550
		send_vblank_event(dev, e, seq, &now);
1551
		vblwait->reply.sequence = seq;
1552
	} else {
1553
		/* drm_handle_vblank_events will call drm_vblank_put */
1554
		list_add_tail(&e->base.link, &dev->vblank_event_list);
1555
		vblwait->reply.sequence = vblwait->request.sequence;
1556 1557 1558 1559 1560
	}

	spin_unlock_irqrestore(&dev->event_lock, flags);

	return 0;
1561 1562 1563 1564 1565

err_unlock:
	spin_unlock_irqrestore(&dev->event_lock, flags);
	kfree(e);
err_put:
1566
	drm_vblank_put(dev, pipe);
1567
	return ret;
1568 1569
}

D
Daniel Vetter 已提交
1570
/*
L
Linus Torvalds 已提交
1571 1572 1573
 * Wait for VBLANK.
 *
 * \param inode device inode.
1574
 * \param file_priv DRM file private.
L
Linus Torvalds 已提交
1575 1576 1577 1578
 * \param cmd command.
 * \param data user argument, pointing to a drm_wait_vblank structure.
 * \return zero on success or a negative number on failure.
 *
1579 1580
 * This function enables the vblank interrupt on the pipe requested, then
 * sleeps waiting for the requested sequence number to occur, and drops
D
Daniel Vetter 已提交
1581
 * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
1582
 * after a timeout with no further vblank waits scheduled).
L
Linus Torvalds 已提交
1583
 */
1584 1585
int drm_wait_vblank(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
L
Linus Torvalds 已提交
1586
{
1587
	struct drm_vblank_crtc *vblank;
1588
	union drm_wait_vblank *vblwait = data;
1589
	int ret;
1590
	unsigned int flags, seq, crtc, high_crtc;
L
Linus Torvalds 已提交
1591

1592 1593
	if (!dev->irq_enabled)
		return -EINVAL;
L
Linus Torvalds 已提交
1594

1595 1596 1597
	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
		return -EINVAL;

1598
	if (vblwait->request.type &
1599 1600
	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
1601
		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1602
			  vblwait->request.type,
1603 1604
			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
			   _DRM_VBLANK_HIGH_CRTC_MASK));
1605 1606 1607
		return -EINVAL;
	}

1608
	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1609 1610 1611 1612 1613
	high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
	if (high_crtc)
		crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
	else
		crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1614
	if (crtc >= dev->num_crtcs)
1615 1616
		return -EINVAL;

1617 1618
	vblank = &dev->vblank[crtc];

1619 1620
	ret = drm_vblank_get(dev, crtc);
	if (ret) {
1621
		DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1622 1623 1624
		return ret;
	}
	seq = drm_vblank_count(dev, crtc);
1625

1626
	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
L
Linus Torvalds 已提交
1627
	case _DRM_VBLANK_RELATIVE:
1628 1629
		vblwait->request.sequence += seq;
		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
L
Linus Torvalds 已提交
1630 1631 1632
	case _DRM_VBLANK_ABSOLUTE:
		break;
	default:
1633 1634
		ret = -EINVAL;
		goto done;
L
Linus Torvalds 已提交
1635 1636
	}

1637 1638 1639 1640
	if (flags & _DRM_VBLANK_EVENT) {
		/* must hold on to the vblank ref until the event fires
		 * drm_vblank_put will be called asynchronously
		 */
1641
		return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1642
	}
1643

1644
	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1645 1646
	    (seq - vblwait->request.sequence) <= (1<<23)) {
		vblwait->request.sequence = seq + 1;
1647 1648
	}

1649 1650
	DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
		  vblwait->request.sequence, crtc);
1651 1652
	vblank->last_wait = vblwait->request.sequence;
	DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
1653 1654
		    (((drm_vblank_count(dev, crtc) -
		       vblwait->request.sequence) <= (1 << 23)) ||
1655
		     !vblank->enabled ||
1656
		     !dev->irq_enabled));
L
Linus Torvalds 已提交
1657

1658 1659
	if (ret != -EINTR) {
		struct timeval now;
L
Linus Torvalds 已提交
1660

1661
		vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1662 1663
		vblwait->reply.tval_sec = now.tv_sec;
		vblwait->reply.tval_usec = now.tv_usec;
1664

1665 1666
		DRM_DEBUG("returning %d to client\n",
			  vblwait->reply.sequence);
L
Linus Torvalds 已提交
1667
	} else {
1668
		DRM_DEBUG("vblank wait interrupted by signal\n");
L
Linus Torvalds 已提交
1669 1670
	}

1671 1672
done:
	drm_vblank_put(dev, crtc);
L
Linus Torvalds 已提交
1673 1674 1675
	return ret;
}

1676
static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1677 1678 1679 1680 1681
{
	struct drm_pending_vblank_event *e, *t;
	struct timeval now;
	unsigned int seq;

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	assert_spin_locked(&dev->event_lock);
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	seq = drm_vblank_count_and_time(dev, crtc, &now);
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	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
		if (e->pipe != crtc)
			continue;
		if ((seq - e->event.sequence) > (1<<23))
			continue;

		DRM_DEBUG("vblank event on %d, current %d\n",
			  e->event.sequence, seq);

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		list_del(&e->base.link);
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		drm_vblank_put(dev, e->pipe);
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		send_vblank_event(dev, e, seq, &now);
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	}

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Jesse Barnes 已提交
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	trace_drm_vblank_event(crtc, seq);
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}

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/**
 * drm_handle_vblank - handle a vblank event
 * @dev: DRM device
 * @crtc: where this event occurred
 *
 * Drivers should call this routine in their vblank interrupt handlers to
 * update the vblank counter and send any signals that may be pending.
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 *
 * This is the legacy version of drm_crtc_handle_vblank().
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 */
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bool drm_handle_vblank(struct drm_device *dev, int crtc)
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{
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	struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
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	u32 vblcount;
	s64 diff_ns;
	struct timeval tvblank;
	unsigned long irqflags;

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	if (WARN_ON_ONCE(!dev->num_crtcs))
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		return false;
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Rob Clark 已提交
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	if (WARN_ON(crtc >= dev->num_crtcs))
		return false;

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	spin_lock_irqsave(&dev->event_lock, irqflags);

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	/* Need timestamp lock to prevent concurrent execution with
	 * vblank enable/disable, as this would cause inconsistent
	 * or corrupted timestamps and vblank counts.
	 */
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	spin_lock(&dev->vblank_time_lock);
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	/* Vblank irq handling disabled. Nothing to do. */
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	if (!vblank->enabled) {
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		spin_unlock(&dev->vblank_time_lock);
		spin_unlock_irqrestore(&dev->event_lock, irqflags);
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		return false;
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	}

	/* Fetch corresponding timestamp for this vblank interval from
	 * driver and store it in proper slot of timestamp ringbuffer.
	 */

	/* Get current timestamp and count. */
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	vblcount = vblank->count;
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	drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);

	/* Compute time difference to timestamp of last vblank */
	diff_ns = timeval_to_ns(&tvblank) -
		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));

	/* Update vblank timestamp and count if at least
	 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
	 * difference between last stored timestamp and current
	 * timestamp. A smaller difference means basically
	 * identical timestamps. Happens if this vblank has
	 * been already processed and this is a redundant call,
	 * e.g., due to spurious vblank interrupts. We need to
	 * ignore those for accounting.
	 */
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	if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS)
		store_vblank(dev, crtc, 1, &tvblank);
	else
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		DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
			  crtc, (int) diff_ns);

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	spin_unlock(&dev->vblank_time_lock);

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	wake_up(&vblank->queue);
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	drm_handle_vblank_events(dev, crtc);
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	spin_unlock_irqrestore(&dev->event_lock, irqflags);

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	return true;
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}
EXPORT_SYMBOL(drm_handle_vblank);
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/**
 * drm_crtc_handle_vblank - handle a vblank event
 * @crtc: where this event occurred
 *
 * Drivers should call this routine in their vblank interrupt handlers to
 * update the vblank counter and send any signals that may be pending.
 *
 * This is the native KMS version of drm_handle_vblank().
 *
 * Returns:
 * True if the event was successfully handled, false on failure.
 */
bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
{
	return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
}
EXPORT_SYMBOL(drm_crtc_handle_vblank);